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• OpenCV4 (python 3.9) VideoCapture failing to open .mp4 file on osx

  15 juin 2021, par Ender

  I am trying to read an mp4 video frame-wise with OpenCV4 installed with brew. The following snippet, though, fails to open the file :

  


  v_path = os.path.join(v_dir, v_title + ".mp4")
v = cv2.VideoCapture(v_path)


  


  resulting in the following error :

  


  OpenCV: Couldn't read video stream from file []


  


  v_path is an absolute path. Some advise searching for the opencv_ffmpeg.dll file and copying it to the root python folder but its not in /usr/local/Cellar/opencv/4.5.2_4/lib and I would rather not download it directly from a site. If this is crucial, how should I reinstall opencv (ideally still using brew) ? The thing is brew include ffmpeg with the opencv installation. Others say converting to .avi with ffmpeg is the trick but there should be a solution for .mp4, right ? Other questions focus on issues where VideoCapture opens the video but is unable to load any frames, this seems like a less severe problem.

  


  brew doctor


  


  reveals no serious issues.

  


• Rotate video without transcode - problems

  29 décembre 2023, par Tyrone Hirt

  I created an FFMpeg script to rotate -90 some videos, this makes these videos display correctly.

  


  the script is this :

  


  ffmpeg -i input.mp4 -c:v copy -metadata:s:v:0 rotate=-90 output.mp4


  


  The issue is that for some reason all the output files are having variations of 2 frames, which causes me problems when I use these files as Proxy videos in editing programs.

  


  For example, if the original file has a timecode of 00:00:32:12 the output file for some reason will have a timecode of 00:00:32:10.

  


  The problem seems to be occurring because I am working with files with 23,976 fps, because I did a test with a video file with 30 fps and there was no variation in the output file.

  


  How can I fix this problem ?

  


  I've already tried adding -r 23.976 to the code to force the frame rate, but that didn't help either.

  


  The crucial point here is to rotate the video without re-encoding the file, as re-encoding will cause a significant time penalty in my workflow.

  


• Evolution #4754 : Mettre à jeu le jeu des icônes de extensions

  30 avril 2021, par b b

  Amha, SVG partout et zou, et si nécessaire on pourra générer du PNG en masse à partir des SVG.

  Je proposais donc le pack Yaru https://github.com/ubuntu/yaru/tree/master/icons/src/fullcolor/mimetypes (icônes d’Ubuntu) complet, sobre mais il est trop coloré et "en relief" maintenant qu’on est plutôt en mode flat sur le jeu d’icônes du privé, exemples :

  https://github.com/ubuntu/yaru/blob/master/icons/src/fullcolor/mimetypes/text-markdown.svg
  https://github.com/ubuntu/yaru/blob/master/icons/src/fullcolor/mimetypes/x-office-spreadsheet.svg

  Sinon, il y a aussi Papirus & Vimix, et surtout Numix qui est très fourni :

  https://github.com/PapirusDevelopmentTeam/papirus-icon-theme/blob/master/Papirus/64x64/mimetypes/application-pdf.svg
  https://github.com/vinceliuice/vimix-icon-theme/blob/master/src/scalable/mimetypes/application-pdf.svg
  https://github.com/numixproject/numix-icon-theme/blob/master/Numix/64/mimetypes/application-pdf.svg